A WKWebView-based streaming markdown / conversation renderer for Apple platforms.
Born inside Cog as the web-renderer experiment for its conversation panel; on 2026-08-03 it became the panel's main line, with an app-agnostic API and zero host-app types. Open-sourced at lcandy2/WKMarkdownKit — development currently happens in the Cog monorepo and is synced here. A single-document core view (WKMarkdownView) is planned as the conversation layer splits from the markdown engine.
Status: macOS and iOS (WKConversationView is
NSViewRepresentable / UIViewRepresentable over one shared web
engine). Requires Swift 6.
Mid-stream frame — the reveal fog trailing the cursor, inline code chips sweeping open with the text:
- Streaming reveal: a continuous cursor at a fixed 40 chars/s drives a spatial two-layer fog (blurred ghost ahead, sharp glyph fading in over it), with paragraph fast-forward, honest parking on stalls, and a low-passed reveal-height clip — no layout jumps.
- Streaming-safe parsing: remend repairs half-open markdown before marked parses; blocks are cached by source (lexer-level), so settled content is never re-rendered.
- Native-grade selection: continuous cross-block text selection with glyph-hugging highlights — all-flex structure (no WebKit selection-gap painting), grid tables, per-line code blocks, generated-content list markers, select-none chrome.
- Conversation chrome: turn folding ("Worked for Xs"), bare tool rows with animated 13px detail wells, in-flow plan approval cards, older-history paging with scroll anchoring, Working… row.
- Code blocks: two-layer card, hover chip (language + copy with stroke-draw confirmation), highlight.js syntax colors.
import WKMarkdownKit
WKConversationView(
payload: ConversationPayload(segments: [...]),
onPlanDecision: { requestId, decision in ... },
onLoadOlder: { ... }
)ConversationPayload is WKMarkdownKit's own schema — hosts map their
domain types into it; the renderer knows nothing about them.
| Dependency | Version | License |
|---|---|---|
| marked | 15.x | MIT |
| highlight.js | 11.11.1 (+ xcode theme) | BSD-3-Clause |
| remend | 1.3.0 | MIT |
MIT — see LICENSE. Vendored dependencies keep their own licenses (table above).